The mission of the Organic Synthesis Core Facility (OSCF) is to provide chemical synthesis services to the MSKCC community, and to maintain a state-of-the art facility with expert professional personnel in chemical synthesis. This Chemistry Core Facility operates at the interface of chemistry, biology and medicine, and has the capability to support medical chemistry efforts to evolve neg agents in support of MSKCC investigators. The work of the Core has greatly facilitated preclinical studies at the Center. The Core synthesizes novel molecules that are not readily available, by either following described procedures or by developing new and more suitable methods of synthesis. MSKCC is committed to the research and development of new tools and therapeutic agents for cancer detection, prevention, and treatment. The specialized services provided by the Organic Synthesis Core have supported the research of 16 investigators in the past year. During the past grant period the work of the Core has contributed to 60 publications of researchers from 5 research programs. For example, the Sawyers laboratory used the Core's services to develop a new androgen receptor antagonist as a potential therapy for prostate cancer. In a relatively short time, the Core was able to invent a new chemical process to synthesize an antagonist that was safe, scalable, and reproducible. Most importantly, controls of delivered batches made it easy to adjust the methodology when batch bioavailability assessments varied significantly. This has so far resulted in two licensed patents, a high profile paper, and most importantly a drug with desirable properties, now known as ARN-509, that will shortly enter Phase III evaluation in castrate resistant prostate cancer.